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Hearing aid with tuned microphone cavityHearing aid with tuned microphone cavity description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070189563, Hearing aid with tuned microphone cavity. Brief Patent Description - Full Patent Description - Patent Application Claims
RELATED APPLICATIONS [0001]This application is related to a co-pending U.S. Utility application entitled "Hearing Aid Circuit With Integrated Switch and Battery," filed on even date herewith, in the name of Walter P. Sjursen, Michael DeSalvo, Hassan Mohamed, Paul J. Mulhouser, and Karl D. Kirk III (Attorney Docket No. 2506.2034-000). This application is also related to a co-pending U.S. Design patent entitled "Hearing Aid," filed on even date herewith, in the name of Walter P. Sjursen, Michael DeSalvo and Hassan Mohamed (Attorney Docket No. 2506.2036-000). The entire teachings of the above applications are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002]A hearing aid, in general, comprises a housing or ear mold which contains a receiver, a microphone, electronic circuitry connecting the receiver and the microphone, and a battery for operating the electronic circuitry. The housing is an ear mold which fits into the ear canal of the user. [0003]In a conventional hearing aid, the microphone converts incident sound waves into an analog electrical signal which is then processed to filter out unwanted noise etc., amplified, and coupled to a receiver or speaker which converts the electrical signal back to sound waves. The electrical signal processor may be an analog processor which operates directly upon an analog electrical signal. Alternatively, the analog signal may be converted to a digital signal and processed by a digital signal processor (DSP). Typically, the signal processing circuitry is designed to provide a particular frequency response in order to compensate for the type of hearing loss suffered by the user. For example, one common type of hearing impairment is the difficulty in hearing soft sounds at high audible frequencies. Thus, it is common for the signal processing scheme of a hearing aid to increase the gain of these high-frequency sounds relative to lower frequency sounds. [0004]There has been a growing need for small, reliable, easy to use low-cost hearing aids. In particular, it would be desirable to be able to provide a low-cost hearing aid design that could meet the needs of the vast majority of users experiencing age related hearing loss. [0005]One approach to meet these goals has been the development of low-cost, mass-produced hearing aids, including disposable hearing aids. The disposable hearing aid is of a structure that is so inexpensive to manufacture that it is possible to merely replace the whole hearing aid, rather than just the battery, when the battery runs out. Thus, the life of a disposable hearing aid is dependent on the life of the battery. Examples of disposable hearing aids are described in, for example, U.S. Pat. No. 5,881,159 to Aceti et al., U.S. Pat. No. 6,058,198 to Aceti et al., U.S. Pat. No. 6,473,511 to Aceti et al., and U.S. Pat. No. 6,865,279 to Leedom, and in U.S. patent application Ser. No. 09/804,978 to Leedom et al., and Ser. No. 10/688,099 to Leedom et al., the entire teachings of which are incorporated herein by reference. [0006]A limiting factor on the development of high-quality, inexpensive hearing aids is that many of the component parts of these devices, such as the signal processing circuitry, remain relatively expensive. Thus, there is a need to further reduce the cost of hearing aids. SUMMARY OF THE INVENTION [0007]A hearing aid comprises a microphone that receives incident sound waves from one or more sources external to the hearing aid, and converts the sound waves into electronic signals; a circuit that amplifies the electronic signals; a receiver that converts the amplified electronic signals into amplified sound waves; and a tuned resonant cavity between the microphone and the at least one external sound source. At least one parameter of the tuned resonant cavity is selected to modify the frequency response of the incident sound waves that are received by the microphone. In particular, the geometry of one or more openings through which sound waves enter the chamber, the geometry of the chamber itself, and/or the geometry of one or more openings through which sound waves exit the chamber, are selected to condition the incident sound waves by modifying the frequency response of the audio signal prior to the signal being received at the microphone. [0008]In one aspect, the tuned resonant cavity acts much like a passive acoustical filter. The geometry of the cavity is designed to provide a desired frequency response in the incident audio signal. For instance, the geometry of the cavity can result in certain audio frequencies, or ranges of frequencies, being amplified or attenuated relative to the other frequencies, resulting in a conditioned or filtered audio signal being received at the microphone. The physical characteristics of the tuned resonant cavity can be represented as an electronic circuit, specifically an RLC circuit, and the frequency response of the sound waves in the cavity can be analyzed by reference to the frequency response of the corresponding electrical circuit representation of the cavity. [0009]In general, the incident sound waves that are conditioned by the resonant cavity can comprise sound waves having frequencies between 1 and 10 kHz, and more specifically between 5 and 7 kHz. The parameters of the resonant cavity that can be selected to condition the incident sound waves include, for example, the number of entrance holes into the cavity, the cross-sectional area of the entrance hole(s), and the shape of the entrance hole(s). In addition, the number of exit holes from the cavity, the cross-sectional area of the exit hole(s) and the shape of the exit hole(s) can also be selected. Other parameters of the resonant cavity that can be selected include the volume of the cavity, the shape of the cavity, and the materials of the cavity. [0010]An advantage of the present hearing aid is that the tuned resonant cavity can be designed to provide a frequency response(s) that help compensate for various types of hearing loss. For instance, the tuned resonant cavity can be designed to increase the gain at higher frequencies relative to lower frequencies in the incident sound signal, since one common type of hearing impairment is a difficulty in hearing low-volume, high-frequency sounds. The tuned resonant cavity can help reduce the cost of the hearing aid, since the passive conditioning of the incident sound waves afforded by the tuned resonant cavity minimizes the requirements of the signal processing electronics. Thus, smaller, less complex, and/or less expensive circuitry can be employed. In addition, because the tuned resonant cavity is a passive component that does not consume any electrical power, the power requirements of the hearing aid are reduced. This is particularly important in the context of a disposable hearing aid, since lower power requirements translate to a longer useful life for the hearing aid. [0011]In certain embodiments, the tuned resonant cavity is an integral component of the hearing aid. For example, the cavity can comprise a portion of a hearing aid shell that contains the hearing aid electronic components (e.g., the microphone, battery, circuitry, and receiver). The hearing aid shell can comprise a face plate having one or more openings for sound waves. The microphone can be mounted generally parallel and spaced away from the face plate within the hearing aid shell, and the tuned resonant cavity can comprise the interior volume of the shell between the face plate and the microphone. Preferably, the tuned resonant cavity is substantially acoustically isolated from the rest of the hearing aid shell. For instance, the microphone can be sealed into the interior of the shell (by a gasket or o-ring, for example), so that sound is contained in the tuned resonant cavity. If necessary, a small opening can be provided to permit air to travel behind the microphone into the interior of the hearing aid shell (for example, to provide oxygen for an air-activated battery). However, the acoustical impedance of this opening is preferably sufficiently high to substantially prevent audible sound waves from exiting the cavity through the opening. [0012]In other embodiments, the tuned resonant cavity comprises a component that is mounted to or within the hearing aid. The cavity can be separately manufactured for incorporation within the hearing aid. An advantage of this is that the geometry of the cavity can generally be more precisely controlled than in the case where the resonant cavity is formed from the hearing aid shell. In certain embodiments, the tuned resonant cavity can comprise a conduit that is mounted in front of the microphone. The conduit can have any practical size and shape. It can have a cross-section that is substantially circular, elliptical, triangular, rectangular, or irregularly-shaped. Preferably, a first end of the conduit contacts a surface of the microphone. The cross-sectional area of the first end of the conduit is preferably approximately equal to the area of the microphone diaphragm, and the first end of the conduit can be substantially aligned with the diaphragm. Preferably, the interface between the first end of the conduit and the microphone diaphragm is substantially sealed, so that the sound waves in the conduit are directed into the microphone diaphragm. [0013]In another aspect, the first end of the conduit comprises a flange that extends radially from the conduit. The conduit can comprise part of a switching mechanism for modifying an operating state of the hearing aid. In one embodiment, at least one switch trace for the switching mechanism is mounted directly or indirectly on the flange of the conduit. For example, a circuit board can be mounted on the flange of the conduit, and at least one switch trace can be located on the circuit board. Preferably, the circuit board comprises a flexible circuit board that is mounted on the flange. The flange supports the flexible circuit board, and functions as a stiffener for the circuit board. [0014]In another aspect, the conduit functions as a shaft such that a component of the switching mechanism rotates around the conduit. Preferably, the switching mechanism comprises a rotary switch that is rotatable around the conduit. The rotary switch can comprise one or more electrical contacts that engage with the switch trace(s) as the rotary switch is rotated around the conduit. [0015]The second end of the conduit receives incident sound waves, and can extend partially or completely through a face plate of the hearing aid. [0016]In another aspect of the invention, a hearing aid comprises a plurality of tuned resonant cavities between the microphone and the at least one external sound source. In certain embodiments, at least two tuned resonant cavities are arranged in series. In yet further embodiments, at least two tuned resonant cavities are arranged in parallel. A series of tuned resonant cavities can be used, for example, to provide a notch filter to selectively modify various frequency bands over a frequency spectrum of interest. [0017]A method for manufacturing a hearing aid comprises providing a microphone that receives incident sound waves from one or more sources external to the hearing aid, and converts the sound waves into electronic signals; providing a circuit that amplifies the electronic signals; providing a receiver that converts the amplified electronic signals into amplified sound waves; selecting parameters for a tuned resonant cavity to modify the frequency response of the incident sound waves; and providing a tuned resonant cavity comprising the selected parameters between the microphone and the at least one external sound source. The selected parameters include at least one of the geometry of one or more openings through which sound waves enter the cavity, the geometry of the cavity, and the geometry of one or more openings through which sound waves exit the cavity. BRIEF DESCRIPTION OF THE DRAWINGS [0018]The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. [0019]FIG. 1 is a side cross-sectional view of one embodiment of a hearing aid with tuned resonant cavity; [0020]FIG. 2A is an electronic circuit representation of the tuned resonant cavity of FIG. 1; Continue reading about Hearing aid with tuned microphone cavity... Full patent description for Hearing aid with tuned microphone cavity Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Hearing aid with tuned microphone cavity patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Hearing aid with tuned microphone cavity or other areas of interest. ### Previous Patent Application: Contact-less electric switch Next Patent Application: System comprising an automated tool and appertaining method for hearing aid design Industry Class: Electrical audio signal processing systems and devices ### FreshPatents.com Support Thank you for viewing the Hearing aid with tuned microphone cavity patent info. 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